Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755025AbYBYOaR (ORCPT ); Mon, 25 Feb 2008 09:30:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754143AbYBYOaF (ORCPT ); Mon, 25 Feb 2008 09:30:05 -0500 Received: from mail.gmx.net ([213.165.64.20]:36723 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754035AbYBYOaD (ORCPT ); Mon, 25 Feb 2008 09:30:03 -0500 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1/xhgdtnPjx9gQroNhfm0eobFOvmVcQFELMLee027 TusevHABfwCzjo Subject: Re: [PATCH] sched: revert load_balance_monitor() From: Mike Galbraith To: Peter Zijlstra Cc: Ingo Molnar , Srivatsa Vaddagiri , Dhaval Giani , linux-kernel In-Reply-To: <1203942167.6242.142.camel@lappy> References: <1203942167.6242.142.camel@lappy> Content-Type: text/plain Date: Mon, 25 Feb 2008 15:29:59 +0100 Message-Id: <1203949799.4688.9.camel@homer.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1867 Lines: 44 On Mon, 2008-02-25 at 13:22 +0100, Peter Zijlstra wrote: > Subject: sched: revert load_balance_monitor() > > The following commit causes a number of serious regressions: > > commit 6b2d7700266b9402e12824e11e0099ae6a4a6a79 > Author: Srivatsa Vaddagiri > Date: Fri Jan 25 21:08:00 2008 +0100 > sched: group scheduler, fix fairness of cpu bandwidth allocation for task groups > > Namely: > - very frequent wakeups on SMP, reported by PowerTop users. > - cacheline trashing on (large) SMP > - some latencies larger than 500ms > > While there is a mergeable patch to fix the latter, the former issues > are IMHO not fixable in a manner suitable for .25 (we're at -rc3 now). > Hence I propose to revert this patch and try again for .26. > > ( minimal revert - leaves most of the code present, just removes the activation > and sysctl interface ). top - 14:05:56 up 3 min, 16 users, load average: 4.31, 2.14, 0.85 Tasks: 218 total, 5 running, 213 sleeping, 0 stopped, 0 zombie Cpu(s): 35.5%us, 64.5%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND 5294 mikeg 20 0 1464 364 304 R 99 0.0 1:00.08 0 chew-max 5278 root 20 0 1464 364 304 R 32 0.0 0:27.86 1 chew-max 5279 root 20 0 1464 360 304 R 32 0.0 0:35.53 1 chew-max 5290 root 20 0 1464 364 304 R 31 0.0 0:29.00 1 chew-max The minimal revert seems to leave group fairness in a worse state than what the original patch meant to fix. Maybe a full revert would be better? -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/